CHLORTHALIDONE FDA MedWatch Direct Reports Summary

These tables and charts are created from 977 voluntary U.S. reports for CHLORTHALIDONE (CHLORTHALIDONE) reported by individuals to the FDA via the MedWatch Reporting System from 2004 through April 28, 2026.

For a summary of adverse events including mandatory reports submitted by pharmaceutical companies (all countries and all reporter types) to the FAERS database, View FDA FAERS CHLORTHALIDONE Report.

Top Adverse Effects Associated with CHLORTHALIDONE (from U.S. FDA Medwatch Reports)

	Side Effect	# of FDA Reports
1	HYPONATRAEMIA	132
2	NAUSEA	61
3	DIZZINESS	57
4	HEADACHE	56
5	HYPOKALAEMIA	56
6	FATIGUE	52
7	LACK OF STRENGTH AND ENERGY (ASTHENIA)	47
8	DIARRHEA	47
9	DEATH	45
10	SHORTNESS OF BREATH	43
11	VOMITING	39
12	JOINT PAIN	33
13	PRODUCT SUBSTITUTION ISSUE	31
14	DRUG INEFFECTIVE	28
15	PAIN	28
16	ACUTE KIDNEY INJURY	27
17	THERAPY CESSATION	27
18	FALL	25
19	CONFUSIONAL STATE	24
20	RASH	24
21	FAINTING	24
22	BLOOD PRESSURE INCREASED	23
23	DEHYDRATION	21
24	LOW BLOOD PRESSURE	21
25	INSOMNIA	21

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CHLORTHALIDONE Total Medwatch Safety Reports by Patient Sex

Male	Female	Unknown	Total
502	446	29	977

Medwatch Reporter Type	Count
Consumer	287
Physician	39
Pharmacist	347
Other Health Professional	165

Top Indications

HIGH BLOOD PRESSURE
Product used for unknown indication
Type 2 diabetes mellitus
HEART FAILURE
Blood pressure measurement

Type of Outcome Reported
Serious: 712
Not Serious: 265
Note: A serious outcome means the adverse event resulted in death, a life threatening condition, hospitalization, disability, congenital anomaly, or other serious condition.

Suspected Role
Primary Suspect: 977
Concomitant Drugs: 713
Note: A single MedWatch report can list more than one drug. This summary includes CHLORTHALIDONE identified as the suspect drug or as a concomitantly taken drug.

FDA Safety-Related Labeling Changes

THALITONE (CHLORTHALIDONE) Discontinued Drug:
FDA Safety-related Labeling Changes

Have experience (good or bad) with THALITONE? Rate THALITONE at Ask a Patient.

For serious adverse events, report them to the FDA by contacting the drug manufacturer or report directly through the MedWatch voluntary reporting form.

NOTES

This report, created by AskaPatient.com, is derived from U.S. drug-related adverse event cases that were reported directly to the FDA using the voluntary MedWatch online or paper reporting system. MedWatch is the voluntary FDA system for consumers, physicians, and others to directly report adverse reactions. The Medwatch initiative was launched in 1993 as a voluntary reporting program for consumers, physicians and other healthcare practitioners.

After processing the received forms, the FDA adds the MedWatch reports to the FDA Adverse Events Reporting System(or FAERS database.) Click here for the complete FAERS report summary, which includes mandatory reports submitted by pharmaceutical companies (worldwide) combined with the MedWatch reports. MedWatch Reports only represent about 5% of the FAERS database. For more, read "Does the FDA's Rapidly Growing Database of Adverse Events Improve Drug Safety?"

The data in this report was obtained from Open FDA. Data was last updated to include reports through January 27, 2026. The reactions, side effects, or "adverse events," represent up to the 20 most frequently occuring events in the database for a drug related to the event.

Open FDA states that it only includes the most recent version of a case report. It also adds the disclaimer: "Do not rely on Open FDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated."

FDA uses the "MedDRA" classification system to describe reported adverse reactions. MedDRA is a standardized medical terminology that facilitates sharing of regulatory information internationally. In some cases, "patient friendly" terms for the layman designated by MedDRA have been substituted for medical jargon. Please contact us with questions about this report.